I put the chain and sprocket drive on the bike again. I did it because I am getting down to one bike and it is the easiest one to keep adjusted. There is less tinkering with it than the rhino friction drive.

I don't think it is any more efficient, but who knows it is at least close or the same as the rhino. I put it on the bike with gears. I put the special wheel on the bike which is a one speed rear sprocket. I decided to leave the derailleur so that I could make it a two speed bike by changing the front sprocket with the gear shift. The derailleur acts as a chain tensioned. The problem was the 3/16 chain would not fit the sprocket on the Currie drive wheel. My fix was to remove the 3/16 chain then run the 1/4 inch chain through the guide and derailleur. It is a tight fit and binds a little but it does work. If I change the gear slowly it will move between the two front sprockets. The smaller sprocket is easier to pedal when starting on a hill, but the big one allows me to catch the freewheel earlier on hills while riding. I can keep the throttle lower and pedal assist it some.

Anyway for right now it seems to work pretty well. I am able to get three sets of 36v/12ah batteries in the trailer so it has pretty good range I think.